Thanks for your reply. But it was not cancelled by OPS. The CICS region got automatically restarted because of this. As far as BFL(big fat loop) is concerned I am also suspecting this. But very strangely the situation occurs for a certain number of records(not fixed always) when one transaction runs and the same thing happens when this transaction runs twice with each transaction and with half number of records. Say suppose if transaction A fails with 2x number of records , same transaction will fail with x number of records if it runs twice at the same time. If loop would have been the case the number of records would have been the same after which loop starts no matter how many transactions run at same time. So I also doubt if anything setup at system level for that transaction (e.g number of records processable at some point of time by that transaction and if it exceeds it will fail abruptly). I have run the transaction with smart test (debugger) also but can't find any loop. Please advise.

So what you are basically telling us is (1) nobody cancelled the region -- even though S222 MEANS SOMEBODY OR SOMETHING CANCELLED THE REGION, and (2) there's no possible way anything could cause the SOS -- EVEN THOUGH THE MESSAGES ARE SHOWING UP.

When you wake up and are willing listen to reality, come back and we'll try to help you resolve the problem. But as long as you deny there is a problem, and refuse to believe the computer which is telling you there is a problem, there's nothing for us to help you with.

Yes the CICS region was restarted by automation no manually. I have tried with increasing EDSA limit for that CICS region but that also couldn't help. So I guess looping is causing problem. But if you read my previous note you can see it's difficult to predict looping. But I will keep investigating. Any suggestion would be greatly appreciated.